1. Field of the Invention
The present invention relates generally to a portable telephone apparatus. More particularly, the present invention relates to a small portable radio telephone whose internal operational code can be easily updated.
2. Background of the Invention
Recently, several types of small portable telephones have been developed for use with various radio telephone systems. Of particular interest are digital cellular telephone systems. Various models of such telephones have different functions and abilities. The telephone company which operates the telephone system may also provide variations in function and features available.
As new telephone services and features became available for such portable telephones, only subscribers who own the latest version of the telephone apparatus can enjoy the full benefits of these new features and services. Other subscribers who own more conventional types of the telephone apparatus may not be able to take full advantage of these newer services and features. In order to obtain access to the new feature or service, these other subscribers have no choice but to either replace the conventional telephone apparatus with the latest model, or to take their apparatus to a service facility for modification. This may be accomplished in some instances by, for example, replacing circuit components such as Integrated Circuits (ICs), applicable for the new service.